Maria Sharapova said 2012 had been the most memorable year of her career after her victory at the French Open and carrying Russia's flag at the opening ceremony of the London Olympics.

"A lot of things came together," she said in Brisbane on Monday. "It was the grand slam that was going to take a little bit longer than the others for me.

"I knew that physically I needed a few extra years to get stronger to move more efficiently on that surface," she said of her win on the French clay.

"The Olympic experience was one that I'll never forget because it was my first time being an Olympian. I was the first Russian female athlete to carry the flag for my country, so it was very emotional. It was such an incredible experience."

Sharapova, competing in this week's Brisbane International tournament, said there was more depth in women's tennis than at any stage of her 12-year career.

"It's much more physical than it has been," she said.

"Maybe five years ago you go into a tournament and you would treat the first couple of rounds as, you know, not as a warmup, but you don't have to go into the first round thinking, okay, this is where I really have to play my best tennis.

"Now it's certainly much different because you can be facing an opponent that's had good results, beaten top players, hasn't been consistent enough but is a really tough, tough player.

"The inconsistency obviously shows that their ranking is not high enough, therefore you're facing them in the first few rounds.

"It is a much stronger sport. And also with technology and racquets and improvements of all the things we have. There are so many things in tennis that in other sports you don't consider: the balls, the racquets, the strings. That changes yearly."

Asked whether she agreed with Serena Williams that a grand slam was possible for one of the top three women players this year, Sharapova described the mission as virtually impossible.

"Well, she has the last two," Sharapova said. "Has she achieved this before? I don't know. She had an incredible season."

Told that Williams had completed the "Serena slam" by winning four straight majors through 2002 and 2003, Sharapova chuckled and replied: "I see. Anything is possible but that's certainly tough. How tough? Well, I've never done it so I can't tell you."

The other member of the big three, world number one Victoria Azarenka who will defend her Australian Open title in Melbourne, said the current era was the toughest in the history of the women's game.

"I truly believe women's tennis is the highest competition right now," she said. "We have a lot of girls who any given day can win a title and beat each other.

"That's very exciting for the public to see and it's exciting for us, the players.

"It gives an extra motivation to know that I have to work hard because if I don't, there is somebody that's going to take my spot. For me personally, I have a lot of excitement for women's competition because I know that I always have to be there."